Work screen display system

ABSTRACT

A work screen display system including a position information obtaining unit for obtaining position information on a work vehicle based on positioning correction information supplied from a first reference station; a region shape determination unit for determining a shape of a specific region where the work vehicle performs autonomous travel, based on positioning correction information supplied from a second reference station; and a display control unit for displaying, on a display unit, a specific region indication section indicating the specific region determined by the region shape determination unit. The display control unit displays the specific region indication section in a display mode that varies between a case where the first and second reference stations are identical and a case where the first and second reference stations are not identical.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/490,461 filed Aug. 30, 2019, which is a national stage applicationunder 35 U.S.C. § 371 of International Pat. App. No. PCT/JP2018/001576filed Jan. 19, 2018, which claims priority under 35 U.S.C. § 119 to JPPat. App. No. 2017-040433 filed Mar. 3, 2017, the disclosures of eachdisclosure are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to a work screen display system fordisplaying a display screen on a display unit when a work vehicle iscaused to perform autonomous travel.

BACKGROUND ART

The work screen display system as those described above is used in anautonomous travel system configured to cause a work vehicle to performautonomous travel (see, e.g., WO2015/119263 (“PTL 1”). A systemdisclosed in PTL 1 includes a radio communication terminal such as atablet terminal and a work vehicle capable of performing autonomoustravel. With this system, a user can operate the radio communicationterminal to give the work vehicle various instructions, such as aninstruction to start autonomous travel, to perform autonomous travel.The radio communication terminal includes a display unit such as adisplay. The display unit includes a screen on which an operationsection indicating the state of the work vehicle and operation sectionsused to give various instructions are displayed, for example.

When autonomous travel is performed, the user operates the radiocommunication terminal while observing the display screen of the displayunit not only before but also after autonomous travel is started. Here,the system disclosed in PTL 1 displays, on the display unit, a displayscreen showing, e.g., an operation section indicating the state of thework vehicle and operation sections used to give various instructions.However, PTL 1 does not describe details of the display screen. Thus, itis desired to display, on a display unit, a display screen withexcellent operability for the user when the work vehicle is caused toperform autonomous travel.

In view of the actual circumstances described above, a main object ofthe present invention is to provide a work screen display system capableof displaying, on a display unit, a display screen with excellentoperability for the user.

SUMMARY OF INVENTION

According to a first aspect, the present invention includes: a positioninformation obtaining unit configured to obtain position information ona work vehicle based on positioning correction information supplied froma first reference station; a region shape determination unit configuredto determine a shape of a specific region where the work vehicle iscaused to perform autonomous travel, based on positioning correctioninformation supplied from a second reference station; and a displaycontrol unit configured to display, on a display unit, a specific regionindication section indicating the specific region determined by theregion shape determination unit, wherein the display control unitdisplays the specific region indication section in a display mode thatvaries between a case where the first reference station and the secondreference station are identical to each other and a case where the firstreference station and the second reference station are not identical toeach other.

According to the above configuration, the display control unit displays,on the display unit, the specific region indication section indicatingthe specific region. Namely, the specific region indication sectionpossesses the position information obtained based on the positioningcorrection information supplied from the second reference station.Meanwhile, the position information obtaining unit obtains the positioninformation on the work vehicle based on the positioning correctioninformation supplied from the first reference station. Thus, in a casewhere the first reference station and the second reference station arenot identical to each other, the pieces of positioning correctioninformation obtained therefrom are different from each other, andtherefore a deviation may potentially occur between the position of thespecific region indication section and the position of the work vehiclepotentially. In order to deal with this, the display control unitdisplays the specific region indication section in a display mode thatvaries between a case where the first reference station and the secondreference station are identical to each other and a case where the firstreference station and the second reference station are not identical toeach other. With this, by checking the display mode of the specificregion indication section, the user can easily determine whether adeviation may potentially occur between the position of the specificregion indication section and the position of the work vehicle. Thus,the user can easily determine the specific region to perform autonomoustravel, and consequently the user can easily and appropriately selectthe specific region, for example. Thus, the above configuration candisplay, on the display unit, the display screen with excellentoperability for the user before start of autonomous travel.

A second aspect of the present invention has the following feature. Thatis, the display control unit displays the specific region indicationsection in a selectable manner either in the case where the firstreference station and the second reference station are identical to eachother or in the case where the first reference station and the secondreference station are not identical to each other, and the displaycontrol unit is capable of displaying identification information on atleast the second reference station in a case where the specific regionindication section is selected.

According to the above configuration, when the specific regionindication section is selected, the display control unit can display theidentification information on at least the second reference stationhaving been used to determine the shape of the specific region. Thus,from the identification information, the user can easily figure outwhich reference station was used as the second reference station.Consequently, the user can determine to which reference station thefirst reference station should be changed in order to make the firstreference station and the second reference station identical to eachother, and the user can perform operation, work, and/or the like forthis purpose.

According to a third aspect, the present invention includes: a positioninformation obtaining unit configured to obtain position information ona work vehicle based on positioning correction information supplied froma first reference station; a region shape determination unit configuredto determine a shape of a specific region where the work vehicle iscaused to perform autonomous travel, based on positioning correctioninformation supplied from a second reference station; and a displaycontrol unit configured to display a map image on a display unit,wherein the display control unit is capable of controlling a displaymagnification of the map image in accordance with operation on aspecific operation section, in a first display state where the specificregion having been determined is displayed on the display unit, thedisplay control unit controls the display magnification of the map imagebased on the specific region, in a second display state where a traveltrajectory of the work vehicle obtained before the determination of thespecific region is displayed on the display unit, the display controlunit controls the display magnification of the map image based on thetravel trajectory, and in a third display state that is not the firstdisplay state or the second display state, the display control unitdisplays the map image at a fixed display magnification.

According to this configuration, by operating a certain operationsection, the user can switch the display state between the first displaystate, the second display state, and the third display state. In thethird display state that is not the first display state or the seconddisplay state, the display control unit displays the map image at afixed display magnification. Thus, the user can view the map image atthe fixed display magnification, and can check the map information in astable manner.

On the other hand, the first display state is for displaying thespecific region. Thus, in the first display state, the display controlunit controls the display magnification of the map image based on thespecific region, e.g., based on the size and/or shape of the specificregion. This facilitates user's observation of the specific region, andalso helps the user appropriately perform operation regarding thespecific region displayed on the display unit. Meanwhile, the seconddisplay state is for displaying the travel trajectory of the workvehicle. Thus, in the second display state, the display control unitcontrols the display magnification of the map image based on the traveltrajectory of the work vehicle. This facilitates user's observation oftraveling of the work vehicle, and also helps the user performappropriate operation regarding the travel trajectory displayed on thedisplay unit.

A fourth aspect of the present invention is as follows. That is, in thefirst display state, the display control unit displays the map image onthe display unit such that the map image is centered on the centroid ofthe specific region, and, in the second display state, the displaycontrol unit displays the map image on the display unit such that themap image is centered on the centroid of the travel trajectory.

According to the above configuration, in the first display state, thedisplay control unit displays the map image on the display unit suchthat the map image is centered on the centroid of the specific region.This facilitates user's observation of the specific region, that is,provides the map image showing the specific region in an easy-to-viewmanner. In the second display state, the display control unit displaysthe map image on the display unit such that the map image is centered onthe centroid of the travel trajectory. This facilitates user'sobservation of the travel trajectory of the work vehicle, that is,provides the map image showing the travel trajectory in an easy-to-viewmanner.

A fifth aspect of the present invention is as follows. That is, thedisplay control unit is capable of displaying a magnified view of themap image in response to operation on a magnifying operation sectionused to magnify the map image, and the display control unit hides, inthe case where the magnifying operation section is operated, at leastone of operation sections that is not the magnifying operation section.

According to this configuration, when the magnifying operation sectionis operated, the display control unit hides at least one of theoperation sections that is not the magnifying operation section. Withthis, the user can easily notice that the magnifying operation sectionhas been operated. Also, this configuration can prevent the situation inwhich the operation section to be hidden is operated and the magnifiedstate of the map image is changed.

A sixth aspect of the present invention is as follows. That is, thedisplay control unit displays the operation section having been hiddenand the magnifying operation section, in a case where the magnifyingoperation section is operated after at least one of the operationsections that is not the magnifying operation section is hidden.

According to this configuration, when the magnifying operation sectionis operated after at least one of the operation sections that is not themagnifying operation section is hidden, the display control unitdisplays the operation section having been hidden and the magnifyingoperation section. Thus, from the situation in which the operationsection having been hidden is displayed again, the user can easilynotice that the magnification of the map image caused by operation onthe magnifying operation section has been cancelled. In addition, sincethe operation section having been hidden is displayed again, it ispossible to operate the operation section thus displayed to change thestate of the map image.

A seventh aspect of the present invention is as follows. That is, thedisplay control unit stores a display setting on the map image appliedprior to the hiding of at least one of the operation sections that isnot the magnifying operation section, and the display control unitdisplays, in response to operation on the magnifying operation sectionperformed after the storing of the display setting, the map imageaccording to the display setting.

According to the above configuration, in response to operation on themagnifying operation section performed after at least one of theoperation sections that is not the magnifying operation section ishidden, the display control unit displays the map image according to thedisplay setting that is stored. Consequently, the screen can easilyreturn to the map image that was displayed prior to the operation on themagnifying operation section. This provides display with an excellentoperability for the user.

According to an eighth aspect, the present invention includes: aposition information obtaining unit configured to obtain positioninformation on a work vehicle based on positioning correctioninformation supplied from a reference station; and a display controlunit capable of providing a predetermined history indication on a travelroute displayed on a display unit based on a travel trajectory of thework vehicle on the travel route formed in a specific region, whereinthe display control unit provides the history indication in a historyindication mode that is either of a first history indication mode inwhich the history indication is provided based on work state informationindicating a work state of the work vehicle and having been obtainedfrom the work vehicle and a second history indication mode in which thehistory indication is provided not based on the work state information.

According to the above configuration, in the first history indicationmode, the display control unit can automatically perform historyindication based on the work state information. In the second historyindication mode, the display control unit can perform history indicationnot based on the work state information but in accordance with user'smanual operation, for example. Thus, the display control unit performseither of the first history indication mode and the second historyindication mode, so as to provide the history indication appropriatelyand flexibly in accordance with changes in, e.g., the states of the workvehicle.

A ninth aspect of the present invention has the following feature. Thatis, the present invention further includes a recording control unitconfigured to record, in a memory unit, the history indication displayedby the display control unit, wherein the recording control unit iscapable of automatically recording, in the memory unit, the historyindication after a predetermined period of time has elapsed since thehistory indication is started by the display control unit, and therecording control unit is capable of recording, in the memory unit, thehistory indication in response to operation on the record instructionoperation section displayed on the display unit.

According to this configuration, since the recording control unitautomatically records, in the memory unit, the history indication aftera predetermined period of time has elapsed since the history indicationis started, it is possible to suppress or reduce the possibility thatthe history indication continues for a long period, thereby making itpossible to prevent shortage of a storage capacity, reduction in aprocessing speed, and the like. In addition, the recording control unitcan record the history indication in the memory unit in response tooperation on the record instruction operation section displayed on thedisplay unit. Thus, by operating the record instruction operationsection, the user can record the history indication in the memory unitat the timing at which the user wishes to perform the recording. Thus,the recording of the history indication in the memory unit can beperformed not only automatically but also in accordance with user'smanual operation. This enables flexible operation, thereby making itpossible to improve the operability.

A tenth aspect of the present invention has the following feature. Thatis, the display control unit is provided to a radio communicationterminal capable of performing radio communication with the workvehicle, the display control unit is capable of displaying a pluralityof screens including a setting screen used to perform setting onautonomous travel of the work vehicle and a work screen via whichinstructions to start and stop autonomous travel of the work vehicle areallowed to be given, the work vehicle is operable in a desired one of aplurality of modes including a normal autonomous travel mode ofperforming the setting on autonomous travel via the setting screen ofthe radio communication terminal and allowing the work vehicle to startautonomous travel in response to an instruction to start autonomoustravel given through the work screen and an autonomous travelpreparation mode of allowing the work vehicle to start autonomous travelin response to an instruction to start autonomous travel given throughthe work screen, without performing the setting on autonomous travel viathe setting screen of the radio communication terminal, and the displaycontrol unit displays the setting screen prior to display of the workscreen in a case where the work vehicle is in the normal autonomoustravel mode, whereas the display control unit displays the work screenwithout displaying the setting screen in a case where the work vehicleis in the autonomous travel preparation mode.

According to the above configuration, while the work vehicle is in thenormal autonomous travel mode, the setting screen is displayed prior todisplay of the work screen. Consequently, it is possible to performvarious settings via the setting screen, and to perform autonomoustravel in accordance with the setting thus set. Meanwhile, while thework vehicle is in the autonomous travel preparation mode, the displaycontrol unit displays the work screen without displaying the settingscreen. Consequently, it is possible to start autonomous travel withoutperforming the setting on autonomous travel via the setting screen.Thanks to omission of displaying of the setting screen, it is possibleto start autonomous travel smoothly.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view illustrating a schematic configuration of an autonomoustravel system.

FIG. 2 is a block diagram illustrating a schematic configuration of theautonomous travel system.

FIG. 3 is a view illustrating a top screen displayed on a display unitof a radio communication terminal.

FIG. 4 is a view illustrating a field registration screen displayed onthe display unit of the radio communication terminal.

FIG. 5 is a view illustrating a field list screen displayed on thedisplay unit of the radio communication terminal.

FIG. 6 is a view illustrating a path list screen displayed on thedisplay unit of the radio communication terminal.

FIG. 7 is a view illustrating a path detail screen displayed on thedisplay unit of the radio communication terminal.

FIG. 8 is a view illustrating a work screen displayed on the displayunit of the radio communication terminal.

FIG. 9 is a view illustrating a work screen displayed on the displayunit of the radio communication terminal.

FIG. 10 is a view illustrating a work screen displayed on the displayunit of the radio communication terminal.

FIG. 11 is a view illustrating a work screen displayed on the displayunit of the radio communication terminal.

FIG. 12 is a view illustrating a work screen displayed on the displayunit of the radio communication terminal.

DESCRIPTION OF EMBODIMENTS

With reference to the drawings, the following will describe anembodiment of an autonomous travel system including a work screendisplay system according to the present invention.

As illustrated in FIG. 1, the autonomous travel system includes atractor 1 that is a work vehicle configured to perform autonomous travelalong a predefined travel route and a radio communication terminal 2with which instructions regarding various kinds of information can begiven to the tractor 1. In the present embodiment, the autonomous travelsystem further includes a reference station 4 capable of transmittingpositioning correction information to the tractor 1 in order to obtainposition information of the tractor 1.

FIG. 1 shows the tractor 1 as one example of the work vehicle. Insteadof the tractor, the work vehicle may be a riding-type working machinesuch as a rice transplanter, a combine harvester, a civil engineeringand construction work machine, and a snowplow, or a walking-type workmachine.

As illustrated in FIG. 2, the tractor 1 includes a vehicle-side radiocommunication unit 14, the radio communication terminal 2 includes aterminal-side radio communication unit 21, and the reference station 4includes a reference-station-side radio communication unit 41. Thetractor 1 and the radio communication terminal 2 are configured to becapable of exchanging various kinds of information with each otherthrough radio communication between the vehicle-side radio communicationunit 14 and the terminal-side radio communication unit 21, and thetractor 1 and the reference station 4 are configured to be capable ofexchanging various kinds of information with each other through radiocommunication between the vehicle-side radio communication unit 14 andthe reference-station-side radio communication unit 41. The radiocommunication terminal 2 and the reference station 4 are configured tobe capable of exchanging various kinds of information with each othervia the tractor 1. Alternatively, the radio communication terminal 2 andthe reference station 4 may be configured to be capable of directlyexchanging various kinds of information with each other not via thetractor 1 but through radio communication between the terminal-sideradio communication unit 21 and the reference-station-side radiocommunication unit 41. These radio communication units may perform radiocommunication therebetween over a common frequency band or differentfrequency bands.

As illustrated in FIG. 2, the tractor 1 includes a positioning antenna11, a vehicle-side control unit 12, a position information obtainingunit 13, the vehicle-side radio communication unit 14, and a memory unit(not illustrated), for example. The vehicle-side control unit 12 isconfigured to enable autonomous travel of the tractor 1 by controllingvarious devices included in the tractor 1, such as a speed governor, atransmission device, and a steering device (each not illustrated), whileobtaining the current position information on itself (the currentposition of the tractor 1) via the position information obtaining unit13. In addition, the tractor 1 includes an inertial measurement unit(not illustrated) having a three-axis gyro sensor, a three-directionacceleration sensor, and/or the like. With this, the vehicle-sidecontrol unit 12 is configured to be capable of detecting the posture ofthe tractor 1, the azimuth of the traveling direction of the tractor 1,and/or the like based on the measurement information given by theinertial measurement unit.

As illustrated in FIG. 1, the positioning antenna 11 is configured toreceive a signal from a positioning satellite 3 included in a satellitepositioning system (GNSS), for example. The positioning antenna 11 isdisposed on the top face of the roof provided on the cabin of thetractor 1, for example.

A positioning method involving use of the positioning system may be apositioning method of obtaining the current position of the tractor 1after correcting satellite positioning information on the tractor 1(mobile station) based on positioning correction information suppliedfrom the reference station 4 installed at a predefined reference point,as illustrated in FIG. 1. For instance, any of various positioningmethods such as differential GPS positioning (DGPS) and real timekinematic positioning (RKT positioning) may be adopted. Alternatively,the positioning method may be independent positioning that does notinvolve use of the reference station 4.

The present embodiment adopts RTK positioning, for example. Thus, asillustrated in FIGS. 1 and 2, the tractor 1, which is the mobilestation, includes the positioning antenna 11, and the reference station4 is used. The position information on the reference point, at which thereference station 4 is installed, is preliminarily set and grasped. Forexample, the reference station 4 is positioned at a place (referencepoint) where the reference station 4 does not interfere with travelingof the tractor 1, e.g., an area surrounding the field. The referencestation 4 includes the reference-station-side radio communication unit41 and a reference-station positioning antenna 42.

In the RTK positioning, both of the reference station 4 installed at thereference point and the positioning antenna 11 of the tractor 1, whichis the target mobile station whose position information is to beobtained, measure the phases of the carrier waves (satellite positioninginformation) from the positioning satellite 3. Every time the referencestation 4 obtains satellite positioning information from the positioningsatellite 3 or every time a preset period has elapsed, the referencestation 4 generates positioning correction information including, e.g.,the satellite positioning information thus obtained and the positioninformation on the reference point. Then, the reference station 4transmits, via the reference-station-side radio communication unit 41,the positioning correction information to the vehicle-side radiocommunication unit 14 of the tractor 1. The position informationobtaining unit 13 of the tractor 1 corrects the satellite positioninginformation obtained by the positioning antenna 11 based on thepositioning correction information supplied from the reference station4, so as to yield the current position information on the tractor 1. Asthe current position information on the tractor 1, the positioninformation obtaining unit 13 obtains latitude/longitude information,for example.

The radio communication terminal 2 is a tablet personal computer with atouch panel, for example. Various kinds of information can be displayedon the touch panel. In addition, by operating the touch panel, it ispossible to enter various kinds of information. The radio communicationterminal 2 is usable either in a state where the user outside thetractor 1 carries the radio communication terminal 2 or in a state wherethe radio communication terminal 2 is attached to, e.g., the side of thedriver seat of the tractor 1.

As illustrated in FIG. 2, the radio communication terminal 2 includesthe terminal-side radio communication unit 21, a display control unit22, a recording control unit 23, a route generating unit 24, a regionshape determination unit 25, and a display unit 26 (touch panel), forexample. The display control unit 22 is configured to display variousscreens on a display screen of the display unit 26. In the followingdescription, in a case where the display control unit 22 displays acertain screen, this means that the display control unit 22 displays thecertain screen on the display unit 26, unless otherwise stated. Theroute generating unit 24 is configured to generate a travel route alongwhich the tractor 1 performs autonomous travel. The radio communicationterminal 2 includes a memory unit (not illustrated), in which variouskinds of information such as information registered by the user isstored.

The tractor 1 is caused to perform autonomous travel in the followingmanner. First, before autonomous travel is started, the user operatesthe radio communication terminal 2 to register field information onfields H, such as the shapes of the fields H where the tractor 1 iscaused to perform autonomous travel (see FIG. 3, the field H correspondsto a specific region). The route generating unit 24 generates travelroutes P (see FIG. 6) for the fields H thus registered. Then, the useroperates the radio communication terminal 2 to select a field H toperform work this time. Thereafter, among the travel routes P havingbeen generated for the field H thus selected, the user selects a travelroute P to perform autonomous travel this time. Upon satisfaction of anautonomous travel initiation condition after the selection of the fieldH and the travel route P, it becomes possible to give an instruction tostart autonomous travel with the radio communication terminal 2. Theuser can operate the radio communication terminal 2 to give theinstruction to start autonomous travel to the tractor 1, so that thetractor 1 starts autonomous travel.

Since the travel route P is generated by the route generating unit 24 ofthe radio communication terminal 2, the radio communication terminal 2needs to transmit route information on the travel route P to the tractor1. Thus, before and/or after start of autonomous travel, the radiocommunication terminal 2 transmits the route information to the tractor1 at a predetermined timing. With this, the vehicle-side control unit 12causes the tractor 1 to perform autonomous travel along the travel routeP based on the route information transmitted from the radiocommunication terminal 2, while obtaining the current positioninformation on the tractor 1 via the position information obtaining unit13. The current position information on the tractor 1 obtained by theposition information obtaining unit 13 is transmitted from the tractor 1to the radio communication terminal 2 in real time (e.g., in periods ofseveral seconds) not only before but also after the start of autonomoustravel. Consequently, the current position T (see FIG. 8) of the tractor1 can be displayed on the display unit 26 of the radio communicationterminal 2.

With reference to FIGS. 3 to 12, the following will describe how thedisplay control unit 22 of the radio communication terminal 2 controlsthe display screen when the tractor 1 is caused to perform autonomoustravel. FIGS. 3 to 12 each illustrate a display screen displayed on thedisplay unit 26 of the radio communication terminal 2.

In response to turning-on of the radio communication terminal 2, thedisplay control unit 22 displays a splash screen, a disclaimer screen,and/or the like, and then displays a top screen illustrated in FIG. 3.The top screen illustrated in FIG. 3 is divided into an upper displayregion 53, which is located close to the upper edge of the screen, and alower display region 54, which is located under the upper display region53. The upper display region 53 is a display screen common to variousscreens (FIGS. 4 to 12) that are displayed after the top screen. Theupper display region 53 is a fixed display region displaying a contentthat will not be changed. Meanwhile, the lower display region 54 is anon-fixed display region in which various display screens are displayedin response to user's selection of operation sections 51.

On the top screen illustrated in FIG. 3, the display control unit 22displays, in the lower display region 54, a plurality of operationsections 51 (various icons in FIG. 3) selectable by the user and a mapimage 52. The display control unit 22 allows a transition to anotherscreen (see, e.g., FIG. 4) in response to selection of a singleoperation section 51 from among the plurality of operation sections 51.

In the center of the screen of the lower display region 54, the mapimage 52 including fields H1 to H7 having been registered is displayed.The display control unit 22 displays the map image 52 at a fixed displaymagnification (this corresponds to a third display state). In addition,the display control unit 22 displays the map image 52 such that theshapes of the fields H1 and H7 are identifiable on the map image 52. Inthe example illustrated in FIG. 3, the fields H1 to H7 on the top screenare each shaped in a quadrangle. At the time of the initial launch ofthe system when no field H has been registered, the map image 52 isdisplayed in such a manner that the map image 52 is centered on acertain position having been set in advance.

The display control unit 22 displays the map image 52 with the center ofthe map image 52 being located at a similar position to that of the mapimage displayed on the display screen the last time. When an operationsection 51 indicated by “CURRENT POSITION” is operated, the displaycontrol unit 22 displays the map image 52 such that the map image 52 iscentered on the current position of the tractor 1.

The display control unit 22 displays the map image 52 such that aprevious work position 55, which is related to the position of thetractor 1 during autonomous travel performed the last time, isidentifiable. The previous work position 55 is indicated by apredetermined mark (pin), which is located at the center of the field H2where the tractor 1 performed autonomous travel the last time. Thedisplay position of the previous work position 55 only needs to show thefield H where autonomous travel was performed the last time. Theprevious work position 55 may alternatively be indicated at a positionat which the work for registering the field H was started or at theentrance to the field H for the tractor 1, for example. Upon completionof the work in the field H, the display control unit 22 displays theprevious work position 55 at the center of the field H. This applies notonly to a case where the last autonomous travel is ended but also to acase where the last autonomous travel is ended on the halfway of thework in the field H.

In the lower display region 54, a field-list-display operation section51 a (the icon indicated by “<-” (left arrow) in FIG. 3), aprevious-work operation section 51 b (the icon indicated by the phrase“START WORK ON PATH USED LAST TIME” in FIG. 3), and other operationsections 51 are displayed in such a manner that these operation sectionssurround the map image 52 except for an upper portion of the map image52.

In the upper display region 53, operation sections 51 indicated by “TOMAP” and “HELP” are displayed close to the left edge, operation sections51 indicated by “GNSS” and “MENU” are displayed close to the right edge,and a display content indicative of a currently displayed screen isdisplayed in the center. The operation section 51 indicated by “TO MAP”is an operation section used to display the map image 52. The operationsection 51 indicated by “GNSS” is an operation section used to displaydetail information on the satellite positioning system and the like,such as a latitude, a longitude, the state of GNSS, the number ofpositioning satellites 3 from which satellite positioning information isobtained, the serial number of the reference station 4, and/or theremaining level of the battery of the base station 4. The operationsection 51 indicated by “MENU” is an operation section to be operated toregister a field H and/or to generate a travel route P through the routegenerating unit 24, for example.

Now, with reference to FIG. 4, the following describes a fieldregistration screen used to register a field H (corresponding to aspecific region). For registration of a field H, it is necessary todetermine the shape of the field H. Thus, as illustrated in FIG. 2, theradio communication terminal 2 includes the region shape determinationunit 25 for determining the shape of the field H. According to variousconditions entered, the route generating unit 24 generates travel routesP (paths) for the field H that has been determined by the region shapedetermination unit 25.

In order to register a field H, the user causes the tractor 1 to travelalong the inner side of the outer periphery of the field H to obtain theposition information on the tractor 1 via the position informationobtaining unit 13 during the traveling. The position informationobtaining unit 13 obtains the current position information on thetractor 1 based on the positioning correction information supplied fromthe reference station 4. The tractor 1 transmits the current positioninformation to the radio communication terminal 2 in real time (e.g., inperiods of several seconds). Based on the current position informationon the tractor 1 supplied in real time, the display control unit 22displays a travel trajectory K of the tractor 1 on the fieldregistration screen illustrated in FIG. 4. The travel trajectory K ofthe tractor 1, which indicates the shape of the field H, can be obtainedin this manner. Based on the travel trajectory K of the tractor 1, theregion shape determination unit 25 determines the shape of the field H.For example, a quadrangular travel trajectory K may be obtained as thetravel trajectory K of the tractor 1 obtained as a result of the tractor1's traveling along the inner side of the outer periphery of the fieldH. In such a case, as shown in the top screen in FIG. 3, the regionshape determination unit 25 determines the shapes of the fields H1 to H7as quadrangles.

On the field registration screen illustrated in FIG. 4, the displaycontrol unit 22 displays, on the map image 52, a travel trajectory K ofthe tractor 1 obtained before the shape of the field H is determined bythe region shape determination unit 25 (this corresponds to a seconddisplay state). Then, the display control unit 22 displays the traveltrajectory K of the tractor 1 until the shape of the field H isdetermined by the region shape determination unit 25.

On the field registration screen illustrated in FIG. 4, the displaycontrol unit 22 controls the display magnification of the map image 52based on the travel trajectory K of the tractor 1. The display controlunit 22 controls the display magnification such that the traveltrajectory K of the tractor 1 is displayed entirely, for example. Inaddition, the display control unit 22 displays the map image 52 suchthat the display screen is centered on the centroid K1 of the traveltrajectory K of the tractor 1.

Referring back to the top screen illustrated in FIG. 3, the followinggives an additional description of a display mode in which the displaycontrol unit 22 displays a field H having been registered. Asillustrated in FIG. 4, positioning correction information supplied froma reference station 4 (corresponding to a second reference station) isused to obtain position information on the tractor 1 in order toregister a field H. Positioning correction information supplied from areference station 4 (corresponding to a first reference station) is usedalso to obtain the current position information on the tractor 1. Here,the number of reference stations 4 is two or more, and the two or morereference stations 4 are positioned at different locations. Thus, merelyfrom simple display of the field H, it is impossible to see if thereference station 4 having been used to register the field H(corresponding to the second reference station) and the referencestation 4 used to obtain the current position of the tractor 1(corresponding to the first reference station) are identical to eachother or different from each other.

In view of this, the display control unit 22 displays the field H havingbeen registered (corresponding to a specific region indication section)in a display mode that varies between a case where the reference station4 having been used to register the field H and the reference station 4used to obtain the current position of the tractor 1 are identical toeach other and a case where the reference station 4 having been used toregister the field H and the reference station 4 used to obtain thecurrent position of the tractor 1 are not identical to each other. Asillustrated in FIG. 3, the field H1, for which the reference station 4having been used to register the field H and the reference station 4used to obtain the current position of the tractor 1 are identical toeach other, is displayed in gray. Meanwhile, the fields H2 to H7, forwhich the reference station 4 having been used to register the field Hand the reference station 4 used to obtain the current position of thetractor 1 are not identical to each other, are displayed in white. Thus,the display mode is varied by use of different colors for displaying thefields. The present invention is not limited to the display modeinvolving use of different colors. The display mode may be selected fromvarious display modes, examples of which encompass a display mode inwhich the field H1, for which the reference stations 4 used areidentical to each other, is displayed with blinking and the fields H2 toH7, for which the reference stations 4 used are not identical to eachother, are displayed with lighting.

When the user selects the field-list-display operation section 51 a (theicon indicated by “<-” (left arrow) in FIG. 3) on the top screenillustrated in FIG. 3, the display control unit 22 causes a transitionfrom the top screen illustrated in FIG. 3 to the field list screenillustrated in FIG. 5.

On the field list screen illustrated in FIG. 5, the lower display region54 is divided into a lower left-side display region 54 a and a lowerright-side display region 54 b. Displayed on the lower left-side displayregion 54 a are the plurality of operation sections 51 and the map image52, which were displayed on the lower display region 54 of the topscreen illustrated in FIG. 3. Displayed on the lower right-side displayregion 54 b are a list 56 of field information stored in the radiocommunication terminal 2 and a travel-route-list display operationsection 51 c (the icon indicated by the phrase “DISPLAY LIST OF PATHS INTHIS FIELD” in FIG. 5) used to display a list of travel routes P (paths)having been generated for a certain field H in the past. In response toselection of any of operation sections 51 indicated by, e.g., “IN ORDEROF DISTANCE”, “IN ORDER OF NAME”, and “IN ORDER OF REGISTRATION”, thelist 56 of the field information can display the information in theorder defined by the selection. In addition, the list 56 of the fieldinformation displays, as the field information on the field H, adistance from the current position of the tractor 1 to the field H, thedate of registration of the field H in the radio communication terminal2, the field position information, and/or the like. In addition, thelist 56 of the field information is displayed with a previous fieldinformation 57 (pin), which indicates, by a predetermined mark, thefield H where the tractor 1 performed autonomous travel the last time.

On the field list screen illustrated in FIG. 5, the display control unit22 can display the list 56 of the field information such that the fieldinformation on each field H is displayed in a display mode that variesbetween a case where the reference station 4 having been used toregister the field H and the reference station 4 used to obtain thecurrent position of the tractor 1 are identical to each other and a casewhere the reference station 4 having been used to register the field Hand the reference station 4 used to obtain the current position of thetractor 1 are not identical to each other. Although not illustrated, thedisplay mode may be varied by, e.g., use of a different color fordisplaying the portion indicated by “Δ” (triangle) in the column fordisplaying the field information. For example, for field information forwhich the reference station 4 having been used to register the field Hand the reference station 4 used to obtain the current position of thetractor 1 are identical to each other, the portion indicated by “Δ”(triangle) may be displayed in red. Meanwhile, for field information forwhich the reference station 4 having been used to register the field Hand the reference station 4 used to obtain the current position of thetractor 1 are not identical to each other, the portion indicated by “Δ”(triangle) may be displayed in while. Alternatively, not only theportion indicated by “Δ” (triangle) but also the entire column fordisplaying the field information may be displayed in a different color.Namely, a portion to be varied in the display mode can be changed asappropriate. The display mode is not limited to the one involving use ofdifferent colors. Alternatively, the display mode may be selected fromvarious other display modes, examples of which encompass the oneinvolving use of different illumination patterns, such as lighting andblinking. Further alternatively, “Δ” (triangle) may not be displayed ina case where the reference station 4 having been used to register thefield H and the reference station 4 used to obtain the current positionof the tractor 1 are not identical to each other, and “Δ” (triangle) maybe displayed only in a case where the reference station 4 having beenused to register the field H and the reference station 4 used to obtainthe current position of the tractor 1 are identical to each other.

When the user selects a certain field H on the field list screenillustrated in FIG. 5 (e.g., when the user selects one of the columnsfor displaying the field information), the display control unit 22displays the selected field H (H3 in FIG. 5) with, e.g., a bold line ofa different color (e.g., a red bold line) surrounding the selected fieldH so that the selected field H can be discriminated from the otherfields H. In addition, the display control unit 22 displays theoperation section 51 having been operated for the selection (the iconindicated by “IN ORDER OF DISTANCE” in FIG. 5) with, e.g., a bold lineof a different color (e.g., a red bold line) surrounding the operationsection 51 so that this operation section 51 can be discriminated fromthe other operation sections 51. At this time, the display control unit22 displays the fields H1 to H7 in such a manner that any of the fieldsH1 to H7 is selectable. Namely, among the fields H1 to H7, not only thefield H1, for which the reference station 4 having been used to registerthe field H and the reference station 4 used to obtain the currentposition of the tractor 1 are identical to each other, but also any ofthe fields H2 to H7, for which the reference station 4 having been usedto register the field H and the reference station 4 used to obtain thecurrent position of the tractor 1 are not identical to each other, isselectable by the user.

When the user selects the travel-route-list display operation section 51c on the field list screen illustrated in FIG. 5 in a state where thecertain field H is selected by the user, the display control unit 22causes a transition from the field list screen illustrated in FIG. 5 tothe path list screen illustrated in FIG. 6.

On the path list screen illustrated in FIG. 6, the lower left-sidedisplay region 54 a displays a map image 52 including a magnified viewof the selected field H, and the lower right-side display region 54 bdisplays a list 59 of path information generated in the past(information on travel routes) and a path transfer operation section 51d (the icon indicated by the phrase “START WORK ON THIS PATH” in FIG. 6)used to transfer, to the tractor 1, information on a selected path(information on a travel route).

On the map image 52 including the magnified view of the field H, thetravel routes P generated by the route generating unit 24 are displayed.In the example illustrated in FIG. 6, the travel routes P each being ina linear shape are displayed such that the travel routes P are arrangedat intervals in a left-right direction.

When the user selects a desired one of the operation sections 51indicated by, e.g., “IN ORDER OF DISTANCE”, “IN ORDER OF NAME”, and “INORDER OF REGISTRATION”, the list 59 of the path information can displaythe pieces of path information having been sorted in the order definedby the selection. Displayed as the path information are a distance fromthe current position of the tractor 1 to the start position of the path,the date of registration in the radio communication terminal 2,information on the start position of the path, and/or the like. Inaddition, the list 59 of the path information displays a path-detaildisplay operation section 51 e (the icon indicated by “DETAILS” in FIG.6) used to display detail information of the path information.Furthermore, the list 59 of the path information displays the pathinformation having been selected (path A in FIG. 6) and the operationsection 51 having been used for the selection (the icon indicated by “INORDER OF NAME” in FIG. 6) with, e.g., bold lines of a different color(e.g., red bold lines) surrounding the selected path information andoperation section 51 so that the selected path information and operationsection 51 can be discriminated from the other path information andoperation sections 51.

When the user selects the path-detail display operation section 51 e onthe path list screen illustrated in FIG. 6 in a state where a certainpath is selected by the user, the display control unit 22 causes atransition from the path list screen illustrated in FIG. 6 to the pathdetail screen illustrated in FIG. 7.

The path detail screen illustrated in FIG. 7 and the path list screenillustrated in FIG. 6 are different from each other only in the displaycontent of the lower right-side display region 54 b. On the lowerright-side display region 54 b of the path detail screen illustrated inFIG. 7, path detail information 60 is displayed. Displayed as the pathdetail information 60 are the area of the field, the presence or absenceof an obstacle, the width of a non-work region (e.g., a headland)located in the surrounding area of a work region where paths (travelroutes) are generated, information on the reference station used for thepath generation, which is related to the reference station 4(corresponding to the second reference station) having been used at thetime of path generation (at the time of registration of the field),information on the reference station currently in connection, which isrelated to the reference station 4 (corresponding to the first referencestation) with which the tractor 1 is currently in communication, tractorinformation, information on a work machine attached to the tractor 1,the number of paths (travel routes), and/or the like.

As the path detail information 60, the information on the referencestation used for the path generation, which is related to the referencestation 4 (corresponding to the second reference station) having beenused at the time of path generation (at the time of registration of thefield), and the information on the reference station currently inconnection, which is related to the reference station 4 (correspondingto the first reference station) with which the tractor 1 is currently incommunication, are displayed. Namely, identification information on thereference station 4 (corresponding to the second reference station) usedat the time of path generation (at the time of registration of thefield) and identification information on the reference station 4(corresponding to the first reference station) with which the tractor 1is currently in communication are displayed. With this, for the field Hselected by the user, it is possible to see whether or not the referencestation 4 having been used to register the field H and the referencestation 4 used to obtain the current position of the tractor 1 areidentical to each other.

Here, in a case where the reference station 4 having been used toregister the field H and the reference station 4 used to obtain thecurrent position of the tractor 1 are not identical to each other, thereference stations 4 from which the pieces of positioning correctioninformation are obtained are different from each other, and therefore adeviation may potentially occur between the current position T of thetractor 1 displayed on the map image 52 and the current position of thetractor 1 actually obtained by the position information obtaining unit13. In order to deal with this, in the case where the reference station4 having been used to register the field H and the reference station 4used to obtain the current position of the tractor 1 are not identicalto each other, the display control unit 22 makes the path transferoperation section 51 d inactive to inhibit selection of the pathtransfer operation section 51 d on the path list screen illustrated inFIG. 6 or the path detail screen illustrated in FIG. 7. In this manner,in the state where the reference station 4 having been used to registerthe field H and the reference station 4 used to obtain the currentposition of the tractor 1 are not identical to each other, start ofautonomous travel is inhibited. The present invention is not limited tothe configuration in which the path transfer operation section 51 d ismade inactive. Alternatively, in the case where the reference station 4having been used to register the field H and the reference station 4used to obtain the current position of the tractor 1 are not identicalto each other, the display control unit 22 may hide the path transferoperation section 51 d, for example. Further alternatively, in the casewhere the reference station 4 having been used to register the field Hand the reference station 4 used to obtain the current position of thetractor 1 are not identical to each other, the user may select whetherto make the path transfer operation section 51 d inactive or to hide thepath transfer operation section 51 d.

In the case where the reference station 4 having been used to registerthe field H and the reference station 4 used to obtain the currentposition of the tractor 1 are identical to each other, the displaycontrol unit 22 changes the status of the path transfer operationsection 51 d from inactive to active. The display control unit 22displays the path transfer operation section 51 d with lighting when thepath transfer operation section 51 d is inactive, and displays the pathtransfer operation section 51 d with blinking when the path transferoperation section 51 d is active, for example. In this manner, thedisplay control unit 22 changes the display mode of the path transferoperation section 51 d so that the user can see whether the pathtransfer operation section 51 d is inactive or active.

When the user selects the path transfer operation section 51 d that isactive on the path list screen illustrated in FIG. 6 or the path detailscreen illustrated in FIG. 7, the path information (information on thetravel routes) is transferred from the radio communication terminal 2 tothe tractor 1 via the terminal-side radio communication unit 21 and thevehicle-side radio communication unit 14. At this time, a radiocommunication check process is performed to check whether or not thepath information transmitted via the terminal-side radio communicationunit 21 and the vehicle-side radio communication unit 14 matches thepath information that the tractor 1 has obtained via the radiocommunication unit 21 and the vehicle-side radio communication unit 14.

In a case where the radio communication check process confirms that thepath information transmitted via the terminal-side radio communicationunit 21 and the vehicle-side radio communication unit 14 matches thepath information that the tractor 1 has obtained via the radiocommunication unit 21 and the vehicle-side radio communication unit 14,the display control unit 22 causes a transition to the work screenillustrated in FIG. 8.

On the work screen illustrated in FIG. 8, the lower display region 54 isvertically divided into three display regions, that is, a lowerupper-side display region 54 c, which is located close to the upperedge, a lower lower-side display region 54 d, which is located close tothe lower edge, and a lower middle display region 54 e, which isinterposed between the lower upper-side display region 54 c and thelower lower-side display region 54 d. The lower middle display region 54e displays the map image 52 including the magnified view of the field Hand the plurality of operation sections 51 displayed in the lowerleft-side display region 54 a on the path list screen illustrated inFIG. 6 or the path detail screen illustrated in FIG. 7. Also, as theoperation sections 51, additional operation sections 51 such as amagnifying operation section 51 h (the icon indicated by “MAGNIFY” inFIG. 8) and a full-screen operation section 51 i (the icon indicated by“ENTIRE VIEW” in FIG. 8) are displayed. The display control unit 22displays, at a fixed display magnification, the map image 52 includingthe magnified view of the field H, and displays, on the map image 52including the magnified view of the field H, the current position T ofthe tractor 1 (this corresponds to the third display state).

In the lower upper-side display region 54 c, a start operation section51 f, with which an instruction to start autonomous travel can be given,is positioned close to the left edge, and a stop operation section 51 g,with which an instruction to stop autonomous travel can be given, ispositioned close to the right edge. The lower lower-side display region54 d displays the operation sections 51 such as a record start operationsection 51 j (the icon indicated by “START RECORDING” in FIG. 8), arecord instruction operation section 51 k (the icon indicated by “STORERECORD” in FIG. 8), and a record deletion operation section 51 m (theicon indicated by “DISCARD RECORD” in FIG. 8) as well as a work progressrate and a work remaining time regarding autonomous travel, for example.

The display control unit 22 makes the start operation section 51 finactive so that the start operation section 51 f cannot be selecteduntil various conditions to start autonomous travel are satisfied. Then,upon satisfaction of the various conditions to start autonomous travel,the display control unit 22 makes the start operation section 51 factive so that the start operation section 51 f can be selected. Thedisplay control unit 22 displays the start operation section 51 f withlighting when the start operation section 51 f is inactive, and displaysthe start operation section 51 f with blinking when the start operationsection 51 f is active, for example. In this manner, the display controlunit 22 changes the display mode of the start operation section 51 f sothat the user can see whether the start operation section 51 f isinactive or active.

When the tractor 1 starts autonomous travel in response to aninstruction to start autonomous travel given with the start operationsection 51 f, the display control unit 22 changes the start operationsection 51 f into a pause operation section 51 f, with which aninstruction to pause autonomous travel can be given, as illustrated inFIG. 9. In response to selection of the pause operation section 51 f,the display control unit 22 changes the start operation section 51 ffrom the pause operation section 51 f into its original display mode. Inthis manner, the display mode of the start operation section 51 f can beswitched between the display mode for giving an instruction to startautonomous travel and the display mode for giving an instruction topause the autonomous travel. With the configuration in which the displaycontrol unit 22 changes the display mode of the start operation section51 f in this manner, a single operation section can function as twooperation sections. In addition, with this configuration, the user caneasily grasp the work situation during autonomous travel, e.g., seewhether autonomous travel has been started or is paused.

On the work screen illustrated in FIG. 8, a distance indicator 62 ispositioned close to the right edge of the lower middle display region 54e. The distance indicator 62 indicates a distance from the currentposition of the tractor 1 to an end (headland) of a travel route P onwhich the tractor 1 is currently performing autonomous travel. Thedistance indicator 62 is a bar-shaped indicator extending in atop-bottom direction. The display control unit 22 extends a lit area ofthe distance indicator 62 step by step from the lower end to the upperend of the distance indicator 62 along with traveling of the tractor 1,as the current position of the tractor 1 advances to a position ahead ofthe end (headland) of the travel route P by a preset distance (e.g., 20m). Then, when the tractor 1 reaches the end (headland) of the travelroute P, the display control unit 22 lights up the whole of the distanceindicator 62. Thereafter, when the tractor 1 reaches the start positionof a next travel route P, the display control unit 22 resets thedistance indicator 62 by turning off the lighting of the whole of thedistance indicator 62. The timing to reset the distance indicator 62 byturning off the lighting of the whole of the distance indicator 62 mayalternatively be a timing when the tractor 1 reaches the end (headland)of the travel route P. The display control unit 22 controls theillumination state of the distance indicator 62 while the tractor 1 istraveling on the travel route P that has a linear shape as illustratedin FIG. 8. Meanwhile, the display control unit 22 does not control theillumination state of the distance indicator 62 while the tractor 1 istraveling on a route such as a turning travel route, for example.

When the user selects the full-screen operation section 51 i on the workscreen illustrated in FIG. 8 or 9, the display control unit 22 displays,on the whole of the lower middle display region 54 e except for theoperation sections 51 and the distance indicator 62, the map image 52including the magnified view of the field H, as illustrated in FIG. 10(this corresponds to the first display state). In this manner, thedisplay control unit 22 controls the display magnification of the mapimage 52 based on the field H in response to selection of thefull-screen operation section 51 i. Also, the display control unit 22displays the map image 52 such that the map image 52 is centered on thecentroid of the field H. When the full-screen operation section 51 i isselected by the user, the display control unit 22 maintains the state inwhich the operation sections 51 arranged near the full-screen operationsection 51 i are displayed.

When the user selects the magnifying operation section 51 h on the workscreen illustrated in FIG. 8 or 9, the display control unit 22 displays,on the whole of the lower middle display region 54 e except for theoperation sections 51 and the distance indicator 62, a map image 52including a magnified view of a range having been set based on thecurrent position T of the tractor 1 in the field H, as illustrated inFIG. 11. As illustrated in FIG. 11, when the user selects the magnifyingoperation section 51 h, the display control unit 22 hides the operationsections 51 arranged near the magnifying operation section 51 h. In FIG.11, below the magnifying operation section 51 h, two operation sections51 (the icons indicated by “+” and “−” in the drawings), the full-screenoperation section 51 i, a single operation section 51 (the iconindicated by “GNSS position” in the drawings) are arranged in a line inthis order from above. However, these five operation sections 51 arehidden.

When the user selects the magnifying operation section 51 h on the workscreen illustrated in FIG. 11, the display control unit 22 causes atransition back to the work screen illustrated in FIG. 8 or 9, so thatthe operation sections 51 hidden on the screen illustrated in FIG. 11are displayed. Here, when the user selects the magnifying operationsection 51 h on the work screen illustrated in FIG. 8 or 9, the displaycontrol unit 22 stores the display setting on the map image 52 appliedat that time. Thus, in response to user's selection of the magnifyingoperation section 51 h on the work screen illustrated in FIG. 11, themap image 52 is displayed on the work screen illustrated in FIG. 8 or 9according to the display setting thus stored. For example, when the userselects the magnifying operation section 51 h on the work screenillustrated in FIG. 8, the display setting such as the displaymagnification on the map image 52 applied at that time is stored, and atransition to the work screen illustrated in FIG. 11 takes place. Then,by selecting the magnifying operation section 51 h on the work screenillustrated in FIG. 11, the user can cause a transition back to the workscreen illustrated in FIG. 8, in which the map image 52 is displayedaccording to the display setting such as the display magnification thusstored.

As illustrated in FIG. 9, during autonomous travel, the display controlunit 22 provides a predetermined history indication 63 on the travelroute P based on the travel trajectory of the tractor 1 on the travelroute P generated in the field H. The history indication 63 is providedso as to correspond to a portion of the travel route P in which portionthe tractor 1 has already traveled. The history indication 63 isachieved by a display process of painting out the already-traveledportion with a predetermined color, for example. With this, the user canreadily see the portion of the travel route P in which portion thetractor 1 has performed the work by autonomous travel.

The display control unit 22 provides, as the predetermined historyindication, the history indication 63 in either of a first historyindication mode in which the history indication 63 is provided based onwork state information indicating a work state of the tractor 1 andhaving been obtained from the tractor 1 and a second history indicationmode in which the history indication 63 is provided not based on thework state information.

In the first history indication mode, the work state information isgenerated based on, e.g., the operation state of the work machineattached to the tractor 1, since the vehicle-side control unit 12 of thetractor 1 possesses the information on the operation state of the workmachine. The tractor 1 transmits the work state information to the radiocommunication terminal 2. Thus, the display control unit 22 of the radiocommunication terminal 2 obtains the work state information as well asthe position information on the tractor 1. Consequently, the displaycontrol unit 22 can grasp a portion of the travel route P in whichportion the tractor 1 is performing the work. According to this, thedisplay control unit 22 provides the history indication 63 for theportion where the tractor 1 has performed the work. As described above,in the first history indication mode, the display control unit 22automatically provides the history indication 63 based on the positioninformation and the work state information on the tractor 1.

In the second history indication mode, the display control unit 22 doesnot automatically provide the history indication 63 based on theposition information and the work state information on the tractor 1,but provides the history indication 63 in accordance with user's manualoperation, as illustrated in FIG. 12. For example, when the user selectsthe record start operation section 51 j to start the history indication63 and then moves the current position T of the tractor 1 on the screenof the display unit 26, the display control unit 22 provides the historyindication 63 so as to correspond to the movement of the currentposition T of the tractor 1. Thus, for example, even in a case where awork machine from which work state information cannot be obtained isattached to the tractor 1, it is possible to select the second historyindication mode to provide the history indication 63 in accordance withuser's manual operation.

Although not illustrated, switchover between the first historyindication mode and the second history indication mode can be performedwith a mode switchover operation section that appears in response toselection of a certain operation section 51. When the first historyindication mode is selected with the mode switchover operation section,the display control unit 22 provides the history indication 63 in thefirst history indication mode. Meanwhile, when the second historyindication mode is selected with the mode switchover operation section,the display control unit 22 provides the history indication 63 in thesecond history indication mode. The record start operation section 51 jin the first history indication mode selected with the mode switchoveroperation section and the record start operation section 51 j in thesecond history indication mode selected with the mode switchoveroperation section are displayed in different colors. The display mode ofthe record start operation section 51 j is varied in this manner. Inaddition, in the second history indication mode, the display controlunit 22 changes the indication of the record start operation section 51j from “START RECORDING” to “PAUSE RECORDING”, for example. Thus, thedisplay control unit 22 makes the record start operation section 51 jserve both as the operation section 51 for starting the historyindication 63 and the operation section 51 for pausing the historyindication 63 in the second history indication mode.

Here, in the first history indication mode, the display control unit 22automatically provides the history indication 63 based on the positioninformation and the work state information on the tractor 1. The displaycontrol unit 22 can perform the first history indication mode not onlywhen the tractor 1 is caused to perform autonomous travel but also whenthe tractor 1 is caused to travel in accordance with user's manualoperation. In addition, the display control unit 22 provides, for thehistory indication 63 in the first history indication mode, a displaymode that varies between a case where the tractor 1 is caused to performautonomous travel and a case where the tractor 1 is caused to travel inaccordance with user's manual operation. The display mode may beselected from various display modes, examples of which encompass the oneinvolving use of different colors for the painting process and the oneinvolving use of different illumination patterns, such as lighting andblinking, for the painting process.

As with the case of the first history indication mode, the displaycontrol unit 22 can perform the second history indication mode not onlywhen the tractor 1 is caused to perform autonomous travel but also whenthe tractor 1 is caused to travel in accordance with user's manualoperation. In addition, the display control unit 22 provides, for thehistory indication 63 in the second history indication mode, a displaymode that varies between a case where the tractor 1 is caused to performautonomous travel and a case where the tractor 1 is caused to travel inaccordance with user's manual operation. The display mode may beselected from various display modes, examples of which encompass the oneinvolving use of different colors for the painting process and the oneinvolving use of different illumination patterns, such as lighting andblinking, for the painting process.

As illustrated in FIG. 2, the radio communication terminal 2 includesthe recording control unit 23. When the display control unit 22 performsthe history indication 63, the recording control unit 23 records, in thememory unit 27, the history indication 63 displayed by the displaycontrol unit 22. The recording control unit 23 is configured to becapable of automatically recording the history indication 63 in thememory unit 27 after a predetermined period of time has elapsed sincethe history indication 63 is started by the display control unit 22. Therecording control unit 23 records, in the memory unit 27, historyindications 63 in association with respective fields H in such a manneras to enable identification of the correspondence between the fields Hand the history indications 63. The recording control unit 23 records,at any of various timings, the history indication 63 in the memory unit27 after a predetermined period of time has elapsed after the historyindication 63 is started. Examples of the various timings encompass atiming at which the radio communication terminal 2 is powered on, atiming at which the work screen illustrated in FIG. 9 or the like isdisplayed, and a timing at which a transition from the work screenillustrated in FIG. 9 or the like to another screen (e.g., the topscreen illustrated in FIG. 3) takes place.

As described above, the recording control unit 23 can automaticallyrecord the history indication 63 in the memory unit 27. In addition, therecord instruction operation section 23 can record the historyindication 63 in the memory unit 27 in response to user's selection ofthe record instruction operation section 51 k on the work screenillustrated in FIG. 9. Thus, at the timing at which the user wishes torecord the history indication 63, the recording control unit 23 canrecord the history indication 63 in the memory unit 27.

When the recording control unit 23 records the history indication 63 inthe memory unit 27, the history indication 63 displayed by the displaycontrol unit 22 is reset. Then, the display control unit 22 can retrievethe history indication 63 recorded in the memory unit 27 to display thehistory indication 63 when the field H is displayed.

When the user selects the record deletion operation section 51 m on thework screen illustrated in FIG. 9, the recording control unit 23 deletesthe history indication 63 stored in the memory unit 27. With this, theuser can delete the history indication 63 at a timing at which the userwishes to delete the history indication 63.

As described above, the display control unit 22 is configured to becapable of displaying a plurality of screens including a setting screenused to perform a setting on autonomous travel of the tractor 1 (e.g.,the top screen illustrated in FIG. 3, the field registration screenillustrated in FIG. 4, the field list screen illustrated in FIG. 5, andthe path list screen illustrated in FIG. 6) and the work screen (e.g.,the work screens illustrated in FIGS. 8 and 9) via which instructions tostart and stop autonomous travel of the tractor 1 can be given.

The tractor 1 can perform autonomous travel in a desired one of aplurality of modes including a normal autonomous travel mode ofperforming the setting on autonomous travel via the setting screen ofthe radio communication terminal 2 and allowing the tractor 1 to startautonomous travel in response to an instruction to start autonomoustravel given through the work screen and an autonomous travelpreparation mode of allowing the tractor 1 to start autonomous travel inresponse to an instruction to start autonomous travel given through thework screen, without performing the setting on autonomous travel via thesetting screen of the radio communication terminal 2.

In order to perform normal work, the tractor 1 is brought into thenormal autonomous travel mode. However, during autonomous travel, anabnormality may occur in the control performed by the display controlunit 22 of the radio communication terminal 2, and/or radiocommunication between the tractor 1 and the radio communication terminal2 may be interrupted, for example. In such a case, the vehicle-sidecontrol unit 12 temporarily stops autonomous travel of the tractor 1,and brings the tractor 1 into the autonomous travel preparation mode,from which autonomous travel can be restarted.

While the tractor 1 is in the normal autonomous travel mode, the displaycontrol unit 22 displays the setting screen (e.g., the top screenillustrated in FIG. 3) prior to display of the work screen (e.g., thework screens illustrated in FIGS. 8 and 9). Thus, in the normalautonomous travel mode, various settings on autonomous travel areperformed via the setting screen, and thereafter the work screen viawhich an instruction to start autonomous travel of the tractor 1 can begiven is displayed.

Meanwhile, while the tractor 1 is in the autonomous travel preparationmode, the display control unit 22 displays the work screen (e.g., thework screens illustrated in FIGS. 8 and 9) without displaying thesetting screen (e.g., the top screen illustrated in FIG. 3). Thus, inthe autonomous travel preparation mode, it is possible to display thework screen via which an instruction to start autonomous travel of thetractor 1 can be given, without displaying the setting screen. Then, itis possible to start autonomous travel via the work screen.Consequently, autonomous travel can be restarted quickly and smoothly.

The present invention is applicable to various work screen displaysystems for displaying a display screen on a display unit when a workvehicle is caused to perform autonomous travel.

REFERENCE SIGNS LIST

-   1, tractor (work vehicle)-   2, radio communication terminal-   4, reference station-   13, position information obtaining unit-   22, display control unit-   23, recording control unit-   25, region shape determination unit-   26, display unit-   27, memory unit-   51 h, magnifying operation section-   51 k, record instruction operation section-   52, map image-   63, history indication-   H, field (specific region)-   K, travel trajectory-   K1, centroid of travel trajectory

1. A work screen display system comprising: a display control unitconfigured to display a map image on a display unit, wherein: based onan identified travel trajectory of a work vehicle, in a first displaystate where a specific region where the work vehicle is caused toperform autonomous travel is displayed on the display unit, the displaycontrol unit is configured to control a display magnification of the mapimage based on the specific region.
 2. The work screen display systemaccording to claim 1, wherein the display control unit is configured todisplay the map image on the display unit such that the map image iscentered on a centroid of the specific region in the first displaystate.
 3. The work screen display system according to claim 1, whereinthe display control unit is configured to display a magnified view ofthe map image in response to an operation on a magnifying operationsection used to magnify the map image.
 4. The work screen display systemaccording to claim 1, wherein the display control unit is configured tohide at least one operation sections that is not a magnifying operationsection.